If I know what AC my enemy hit, I can use that information to decide whether to use abilities such as shield or defensive duelist, and only use it if it would cause that attack to miss. If I merely know that my enemy hit but not what they hit, I might spend the ability (and the reaction) to absolutely no benefit. Which way is it supposed to work?
It's up to your DM. Nothing in the Player's Handbook explicitly entitles players to what a DM rolled and the Dungeon Master's Guide basically leaves it up to the DM whether they want to roll the dice openly or behind a DM screen. Your DM can choose to reveal the total, the dice roll, or no additional info besides the fact that a hit occurred.
It's problematic for NPCs (the player can't tell the DM 'I hit' unless the DM reveals the monster's AC, but if he says what he hit the DM is deciding based on knowing what the roll was), and in general I'm not fond of a rule that makes table style so important (this can also be an issue for bardic inspiration), but short of changing what those effects do, I guess there isn't really a way around it. So, opinions on which version is better balanced?
It's problematic for NPCs (the player can't tell the DM 'I hit' unless the DM reveals the monster's AC, but if he says what he hit the DM is deciding based on knowing what the roll was), and in general I'm not fond of a rule that makes table style so important (this can also be an issue for bardic inspiration), but short of changing what those effects do, I guess there isn't really a way around it. So, opinions on which version is better balanced?
The good news regarding Shield is that it lasts until the start of your next turn, which means you have three pieces of information to help you decide to cast it: your AC currently, the fact that it hit, and approximately how long it will last providing you the extra AC. 25% reduction in hits is pretty good all the time and is still effective even if the opposing party is playing meta and avoiding attacking the character casting shield.
It's problematic for NPCs (the player can't tell the DM 'I hit' unless the DM reveals the monster's AC, but if he says what he hit the DM is deciding based on knowing what the roll was), and in general I'm not fond of a rule that makes table style so important (this can also be an issue for bardic inspiration), but short of changing what those effects do, I guess there isn't really a way around it.
I don't think "problematic" is the right word to describe the situation. D&D is inherently asymmetrical. The DM is entitled to all of the player's statistics and rolls, and they also have all of the info on the environment and NPCs. Also, monster stat blocks are deliberately designed differently from player characters. Mechanics like paralysis or counterspells are deliberately reserved for exceptional monsters because the suck to be on the receiving end of as a player. The DM can't be taken out of the action. Finally, monsters are expendable; the players aren't.
So, opinions on which version is better balanced?
This is completely subjective and in the long run you'll get very similar results no matter which option you pick. Shield is a no-brainer; you're almost always better off casting it.
I'm partial to revealing the d20 roll because in the moment, it adds a bit of tension and makes the player feel like they're making an informed, meaningful decision. If the know the total there's literally no choice, and not giving them any info makes them feel slighted the few times it doesn't help against that hit, even though it'll probably help later anyways. This is especially true at 1st and 2nd level where casters only have two or three 1st level slots.
The good news regarding Shield is that it lasts until the start of your next turn, which means you have three pieces of information to help you decide to cast it: your AC currently, the fact that it hit, and approximately how long it will last providing you the extra AC. 25% reduction in hits is pretty good all the time and is still effective even if the opposing party is playing meta and avoiding attacking the character casting shield.
This. Anyone that's ever been part of an encounter with a Flameskull ought to know how incredibly powerful Shield is. When the average combat lasts 5 rounds or less, getting +5 AC retroactively for a whole round is huge no matter what level you're at. Past level 5 those 1st level slots are mostly worthless in combat anyways.
If I know what AC my enemy hit, I can use that information to decide whether to use abilities such as shield or defensive duelist, and only use it if it would cause that attack to miss. If I merely know that my enemy hit but not what they hit, I might spend the ability (and the reaction) to absolutely no benefit. Which way is it supposed to work?
It's up to your DM. Nothing in the Player's Handbook explicitly entitles players to what a DM rolled and the Dungeon Master's Guide basically leaves it up to the DM whether they want to roll the dice openly or behind a DM screen. Your DM can choose to reveal the total, the dice roll, or no additional info besides the fact that a hit occurred.
You are not supposed to know. You are lucky enough to know that they would have hit if you had not used the spell.
The implication is that the DM doesn't tell you what they rolled, but some do and some don't.
It's problematic for NPCs (the player can't tell the DM 'I hit' unless the DM reveals the monster's AC, but if he says what he hit the DM is deciding based on knowing what the roll was), and in general I'm not fond of a rule that makes table style so important (this can also be an issue for bardic inspiration), but short of changing what those effects do, I guess there isn't really a way around it. So, opinions on which version is better balanced?
The good news regarding Shield is that it lasts until the start of your next turn, which means you have three pieces of information to help you decide to cast it: your AC currently, the fact that it hit, and approximately how long it will last providing you the extra AC. 25% reduction in hits is pretty good all the time and is still effective even if the opposing party is playing meta and avoiding attacking the character casting shield.
I don't think "problematic" is the right word to describe the situation. D&D is inherently asymmetrical. The DM is entitled to all of the player's statistics and rolls, and they also have all of the info on the environment and NPCs. Also, monster stat blocks are deliberately designed differently from player characters. Mechanics like paralysis or counterspells are deliberately reserved for exceptional monsters because the suck to be on the receiving end of as a player. The DM can't be taken out of the action. Finally, monsters are expendable; the players aren't.
This is completely subjective and in the long run you'll get very similar results no matter which option you pick. Shield is a no-brainer; you're almost always better off casting it.
I'm partial to revealing the d20 roll because in the moment, it adds a bit of tension and makes the player feel like they're making an informed, meaningful decision. If the know the total there's literally no choice, and not giving them any info makes them feel slighted the few times it doesn't help against that hit, even though it'll probably help later anyways. This is especially true at 1st and 2nd level where casters only have two or three 1st level slots.
This. Anyone that's ever been part of an encounter with a Flameskull ought to know how incredibly powerful Shield is. When the average combat lasts 5 rounds or less, getting +5 AC retroactively for a whole round is huge no matter what level you're at. Past level 5 those 1st level slots are mostly worthless in combat anyways.